SF bug #1296433 (Expat bug #1515266): Unchecked calls to character data

handler would cause a segfault.  This merges in Expat's lib/xmlparse.c
revisions 1.154 and 1.155, which fix this and a closely related problem
(the later does not affect Python).

Moved the crasher test to the tests for xml.parsers.expat.

Lib/test/crashers/xml_parsers.py

@@ -1,56 +0,0 @@
-from xml.parsers import expat
-
-# http://python.org/sf/1296433
-
-def test_parse_only_xml_data():
-    #
-    xml = "<?xml version='1.0' encoding='iso8859'?><s>%s</s>" % ('a' * 1025)
-    # this one doesn't crash
-    #xml = "<?xml version='1.0'?><s>%s</s>" % ('a' * 10000)
-
-    def handler(text):
-        raise Exception
-
-    parser = expat.ParserCreate()
-    parser.CharacterDataHandler = handler
-
-    try:
-        parser.Parse(xml)
-    except:
-        pass
-
-if __name__ == '__main__':
-    test_parse_only_xml_data()
-
-# Invalid read of size 4
-#    at 0x43F936: PyObject_Free (obmalloc.c:735)
-#    by 0x45A7C7: unicode_dealloc (unicodeobject.c:246)
-#    by 0x1299021D: PyUnknownEncodingHandler (pyexpat.c:1314)
-#    by 0x12993A66: processXmlDecl (xmlparse.c:3330)
-#    by 0x12999211: doProlog (xmlparse.c:3678)
-#    by 0x1299C3F0: prologInitProcessor (xmlparse.c:3550)
-#    by 0x12991EA3: XML_ParseBuffer (xmlparse.c:1562)
-#    by 0x1298F8EC: xmlparse_Parse (pyexpat.c:895)
-#    by 0x47B3A1: PyEval_EvalFrameEx (ceval.c:3565)
-#    by 0x47CCAC: PyEval_EvalCodeEx (ceval.c:2739)
-#    by 0x47CDE1: PyEval_EvalCode (ceval.c:490)
-#    by 0x499820: PyRun_SimpleFileExFlags (pythonrun.c:1198)
-#    by 0x4117F1: Py_Main (main.c:492)
-#    by 0x12476D1F: __libc_start_main (in /lib/libc-2.3.5.so)
-#    by 0x410DC9: (within /home/neal/build/python/svn/clean/python)
-#  Address 0x12704020 is 264 bytes inside a block of size 592 free'd
-#    at 0x11B1BA8A: free (vg_replace_malloc.c:235)
-#    by 0x124B5F18: (within /lib/libc-2.3.5.so)
-#    by 0x48DE43: find_module (import.c:1320)
-#    by 0x48E997: import_submodule (import.c:2249)
-#    by 0x48EC15: load_next (import.c:2083)
-#    by 0x48F091: import_module_ex (import.c:1914)
-#    by 0x48F385: PyImport_ImportModuleEx (import.c:1955)
-#    by 0x46D070: builtin___import__ (bltinmodule.c:44)
-#    by 0x4186CF: PyObject_Call (abstract.c:1777)
-#    by 0x474E9B: PyEval_CallObjectWithKeywords (ceval.c:3432)
-#    by 0x47928E: PyEval_EvalFrameEx (ceval.c:2038)
-#    by 0x47CCAC: PyEval_EvalCodeEx (ceval.c:2739)
-#    by 0x47CDE1: PyEval_EvalCode (ceval.c:490)
-#    by 0x48D0F7: PyImport_ExecCodeModuleEx (import.c:635)
-#    by 0x48D4F4: load_source_module (import.c:913)

Lib/test/test_pyexpat.py

@@ -365,3 +365,24 @@ parser.Parse('''<a>
   <c/>
  </b>
 </a>''', 1)
+
+
+def test_parse_only_xml_data():
+    # http://python.org/sf/1296433
+    #
+    xml = "<?xml version='1.0' encoding='iso8859'?><s>%s</s>" % ('a' * 1025)
+    # this one doesn't crash
+    #xml = "<?xml version='1.0'?><s>%s</s>" % ('a' * 10000)
+
+    def handler(text):
+        raise Exception
+
+    parser = expat.ParserCreate()
+    parser.CharacterDataHandler = handler
+
+    try:
+        parser.Parse(xml)
+    except:
+        pass
+
+test_parse_only_xml_data()

Modules/expat/xmlparse.c

@@ -2552,6 +2552,8 @@ doContent(XML_Parser parser,
                                  (int)(dataPtr - (ICHAR *)dataBuf));
             if (s == next)
               break;
+            if (ps_parsing == XML_FINISHED || ps_parsing == XML_SUSPENDED)
+              break;
             *eventPP = s;
           }
         }